This invention relates to a coupling for connecting a conduit to a junction box.
Numerous types of couplers and connector assemblies are readily available for connecting conduits to junction boxes. Typically, such junction boxes are used in electrical connections where it is referred to as a connection box, an outlet box, or a junction box, and it contains a plurality of apertures through which are connected various types of conduits. The connectors typically include a nipple extending from the junction box, with the nipple having an internal bore for receiving the conduit. The nipple is secured onto the junction box, and an external nut threads onto the nipple and secures the conduit to the nipple.
One such type of connector is described in U.S. Pat. No. 1,030,237. In that patent, the nipple includes an internal flange. The nipple is inserted through the aperture of the electric junction box with the flange abutting the inside wall of the junction box. The nipple is secured to the junction box by means of an external lock nut. The conduit is then inserted into an internal bore in the nipple until the conduit abuts a shoulder provided within the bore. The conduit is externally scored and appropriate wedging metal is placed around the conduit. A cap member threads onto the nipple and forces the wedges into the scored portions of the conduit to secure the conduit in place.
While such connector can function adequately to retain the conduit in place, it requires a number of separate securing steps in order to effect the connection. Firstly, the nipple must be separately secured to the junction box, and subsequently, in a separate securing step, the conduit is secured to the nipple. Additionally, it requires the scoring on the exterior surface of the conduit and requires the utilization of the wedges.
Another common way of griping the conduit is through the use of a split compression ring. Such rings are described in U.S. Pat. Nos. 1,809,582 and 1,888,343. The compression ring typically has a substantially arcuate or V-shaped cross section. The compression ring is placed over a conduit and is sandwiched between a nipple and a compression cap whereby the compression ring is deformed forcing together the opposing side edges of the compression ring, thereby reducing the diameter of the compression ring and forcing it into a gripping engagement with the conduit.
In both of these latter arrangements although a compression ring is provided for the gripping of the conduit, the nipple extending from the junction box is either integrally formed with the junction box or separately retained in place by means of an internal or external locking nut. As a result, there is still needed two separate steps, one for securing the nipple to the junction box and the other to secure the conduit to the nipple.
Accordingly, there appears to be a need for an improved coupling arrangement which permits the coupling of the conduit to the junction box using a single tightening step without the need of a separate locking of the coupling to the junction box and a separate locking of the conduit to the coupling.